General Information

Clarinex (desloratadine) is a histamine-1 (H1) receptor antagonist. Clarinex-D is an extended-release tablet containing a combination of desloratadine and pseudoephedrine sulfate, an alpha adrenergic agonist.

Clarinex is specifically indicated for:

• Seasonal Allergic Rhinitis: relief of nasal and non-nasal symptoms in patients 2 years of age and older
• Perennial Allergic Rhinitis: relief of nasal and non-nasal symptoms in patients 6 months of age and older
• Chronic Idiopathic Urticaria: symptomatic relief of pruritus, reduction in the number of hives, and size of hives in patients 6 months of age and older.

Clarinex-D is specifically indicated for:

• Relief of nasal and non-nasal symptoms of seasonal allergic rhinitis, including nasal congestion, in adults and adolescents 12 years of age and older.

Clarinex is supplied as Tablets, RediTabs , and Oral Solution. The recommended dosing/administration is as follows:

Adults and Adolescents 12 Years of Age and Over:

• Clarinex Tablets - one 5 mg tablet once daily or
• Clarinex RediTabs Tablets - one 5 mg tablet once daily or
• Clarinex Oral Solution - 2 teaspoonfuls (5 mg in 10 mL) once daily

Children 6 to 11 Years of Age:

• Clarinex Oral Solution - 1 teaspoonful (2.5 mg in 5 mL) once daily or
• Clarinex RediTabs Tablets - one 2.5 mg tablet once daily

Children 12 Months to 5 Years of Age:

• Clarinex Oral Solution - 1/2 teaspoonful (1.25 mg in 2.5 mL) once daily

Children 6 to 11 Months of Age:

• Clarinex Oral Solution - 2 mL (1 mg) once daily

Clarinex-D is supplied as 12 HOUR Extended Release Tablets. For adults and adolescents 12 years of age and over the recommended dose of Clarinex-D 12 HOUR Extended Release Tablets is one tablet twice a day.

Mechanism of Action

Desloratadine is a long-acting tricyclic histamine antagonist with selective H1-receptor histamine antagonist activity. Receptor binding data indicates that at a concentration of 2-3 ng/mL (7 nanomolar), desloratadine shows significant interaction with the human histamine H1-receptor. Desloratadine inhibited histamine release from human mast cells in vitro.

Pseudoephedrine sulfate is an orally active sympathomimetic amine and exerts a decongestant action on the nasal mucosa. Pseudoephedrine sulfate is recognized as an effective agent for the relief of nasal congestion due to allergic rhinitis. Pseudoephedrine produces peripheral effects similar to those of ephedrine and central effects similar to, but less intense than, amphetamines. It has the potential for excitatory side effects.

Side Effects

Adverse events associated with the use of Clarinex may include (but are not limited to) the following:

• Pharyngitis
• Dry mouth
• Nausea
• Dizziness
• Somnolence
• Fatigue
• Myalgia

Adverse events associated with the use of Clarinex-D may include (but are not limited to) the following:

• insomnia
• headache
• mouth dry
• fatigue
• somnolence
• pharyngitis
• dizziness
• nausea
• anorexia

Clinical Trial Results

Approval of Clarinex for AR treatment is supported by four double-blind, placebo-controlled studies that enrolled over 2,300 SAR sufferers and two double-blind, placebo-controlled trials with over 1,000 subjects with PAR Results show that a single 5 mg dose of Clarinex provides 24 hours of relief from nasal and non-nasal SAR symptoms. During trials, Clarinex provided significantly greater relief than placebo. 

Approval for CIU is based on two double-blind, placebo-controlled studies involving 416 subjects. Treatment with Clarinex significantly reduced the severity of pruritis when compared to placebo. Clarinex also performed superior to placebo at reducing the number and size of hives.

The clinical efficacy and safety of Clarinex-D 12 HOUR Extended Release Tablets was evaluated in two 2-week multicenter, randomized parallel group clinical trials involving 1248 subjects 12 to 78 years of age with seasonal allergic rhinitis, 414 of whom received Clarinex-D 12 HOUR Extended Release Tablets. In the 2 trials, subjects were randomized to receive Clarinex-D 12 HOUR Extended Release Tablets twice daily, Clarinex Tablets 5 mg once daily, or sustained-release pseudoephedrine tablet 120 mg twice daily for 2 weeks. Primary efficacy variable was twice-daily reflective patient scoring of 4 nasal symptoms (rhinorrhea, nasal stuffiness/congestion, nasal itching, and sneezing) and four non-nasal symptoms (itching/burning eyes, tearing/watering eyes, redness of eyes, and itching of ears/palate) on a 4 point scale (0=none, 1=mild, 2=moderate, and 3=severe). In both trials, the antihistaminic efficacy of Clarinex-D 12 HOUR Extended Release Tablets, as measured by total symptom score excluding nasal congestion, was significantly greater than pseudoephedrine alone over the 2-week 9 treatment period; and the decongestant efficacy of Clarinex-D 12 HOUR Extended Release Tablets, as measured by nasal stuffiness/congestion, was significantly greater than Clarinex (desloratadine alone) over the 2-week treatment period.